I suspect many brands could be handwelted for a good price. Many brands could also lower their margins and sell at a bit smaller profit.
But why would you?
That's the problem.
The only way to get around i is if the customer refuses to buy GY welted shoes.

99% of the public knows nothing about construction, quality materials, etc...AND they do NOT care to. They know Brands and Styles they like. That is all.